Chromium-containing phenolic amine reaction product



Patented Aug. 30, 1949 CHBOMIUM-CONTAINING PHENOI JC ALIINE REACTION PRODUCT Paul R. McCarthy, Allison Park, Pa., assignor to Gulf Research 8: Development Company, Pittsburgh, Pa., a corporation of Delaware No Drawing.

Application October 17, 1946, Serial No. 703,711

4 Claims. (Cl. 260-438) This invention relates to new compositions of matter adapted to inhibit or prevent the corrosion or rusting of metals when applied thereto in the form of a coating.

In the shipping and storage of metal articles, particularly ferrous metal articles having machined surfaces, it is highly desirable to protect such articles from the corrosion and rusting which normally occur when metal surfaces are exposed to the atmosphere for any length of time. While such protection should remain eii'ective over long periods of time under very adverse conditions of humidity, it should likewise be of such nature that it can readily be removed when it is desired to place the metal article into use. Among the various means employed for providing such protection against corrosion, that of applying a iilm or coating of a corrosion inhibiting liquid composition to the metal surface has enjoyed widest use by reason of its economy and adaptability to all sorts of metal articles ranging from simple pieces to complicated machine assemblies. Such liquid corrosion preventive compositions often comprise a mineral or other non-drying oil base having a corrosion preventive material dispersed or dissolved therein, and are hence usually referred to generically as slushing o even though in some instances they may not actually contain an oil.

The slushing oils heretofore employed, however. have been subject to numerous disadvantages. In some instances they have been too expensive for widespread general use whereas in others they are too dlillcult to remove from surfaces to which they have been applied. Many of them have not proved effective over sufllciently long periods of time, or have not provided the desired degree of protection against corrosion under extreme climatic conditions such as those encountered in the tropics or at sea.

Accordingly, it is an object of this invention to trioxide with a phenolic amine compound having the general formula:

wherein R represents an alkyl group, R represents a short chain alkyl group, i. e., an alkyl group containing from 1 to 4 carbon atoms and n represents a whole number less than 3. Examples of such compounds are o-dimethylaminomethyl-m-cresol, o-dimethylaminoethyl-o-ethylphenol, o dimethylamino methyl p butylphenol, o dibutylaminomethyl p -tertiarybutyl phenol, o dimethylaminomethyl p octylphenol, etc. A particularly advantageous member of this class is o-dimethylamino-ethyl-p-tertiarybutyl-phenol, which is available commercially under the trade name Hyamine-B.

Thereaction between chromium trioxide and the herein defined phenolic amine compounds to form the new products which are adapted to be provide new compositions capable of use in inhibiting or preventing the corrosion or rusting of metal surfaces over long periods oi time and under adverse climatic conditions.

Another object is to provide new compositions which can readily be dissolved or dispersed in a suitable liouid vehicle to form inex ensive and highly effective slu hing oil compositions.

Other objects w ll be a parent from the following detailed description of the invention. and various advantages not s ecifically referred to herein will occur to those skilled in the art upon employment of the invention in practice.

I I have found that the above objects and attendant advantages may be realized in certain new corrosion preventives obtained as products of re-. action between chromium trioxide and certain tertiary phenolic am ne compounds. More particularly, I have found that products having exemployed as corrosion preventives is carried out by heating the phenolic amine compound with between about 5 and about 25, preferably between about 8 and 12, per cent by weight thereof of chromium trioxide. The latter is conveniently employed in the form of a 10-20 per cent aqueous solution, although it may be used in crystalline form. The reaction takes place readily at temperatures between about 100 C. and 250 C., and its completion is usually indicated by the reaction mixture assuming the dark green color which is characteristic of certain chromic compounds. Upon completion of the reaction, the mixture is preferably washed with hot water to remove any unreacted chromium trioxide, whereby the reaction product is obtained as a high-boiling viscous mixture which is substantially insoluble in water but is readily soluble in a. variety of organic solvents, e. g., hexane, benzene, carbon tetrachloride, petroleum ether, etc.

The exact identity of the chromium-containing:

reaction products thus obtained and the nature of the reaction by which they are formed are n03 accurately known, and accordingly the reactio products are herein disclosed and claimed as such rather than as chemical compounds whose iden- I '3 solvent, such as hexane, benzene, petroleum ether, carbon tetrachloride, or alight naphtha to form slushing oil compositions of a viscosity suitable for application to metal surfaces by dipping. brushing, or spraying procedures. Such light solvent willevaporate leaving a thin protective coating of the corrosion inhibiting reaction product on the metal surface. When it is desired to use the metal article thus protected, the corrosion preventive coating may readily be removed by washing with a suitable solvent. Gasoline is an excellent solvent for this purpose since it is cheap and universally available. The light petroleum distillate known as Stoddard solvent has been found particularly suitable for use as the solvent in preparing liquid protective coatingcompositions comprising the new corrosion preventives, and may also be used in the subsequent removal of the protective coating.

The amount of solvent employed will depend upon the nature of the solvent itself as well as upon the thickness of the coating desired on the metal surface. Ordinarily, however, suitable compositions will contain up to about 75 per cent, preferably between about and about 75 per 25 cent, by we ght of the solvent. When it is desired to apply a thick corrosion preventive coating, the amount of solvent is kept near the minimum, whereas if a thin coating is preferred, the amount of solvent may be considerably increased. For most applications, a composition comprising equal parts of solvent and the corrosion preventive material will be found very satisfactory.

In addition to being employed per se or in the form of the above-described liquid coating compositions, the corrosion preventive reaction products of the present invention may advantageously be employed in conjunction with other corrosion inhibitors, particularly the so-called "Alox" corrosion preventives manufactured by the Alox Corporation. These latter products are complex mixtures containing hydrocarbons, secondary and tertiary aliphatic alcohols, aliphatic ketones, ketoalcohols, and high molecular weight saturated aliphatic carboxylic and hydroxycarboxylic acids. They are obtained by the Burwell process of partially: oxidizing petroleum hydrocarbons in the liquid phase at elevated temperatures and pressures as disclosed in U. S. Patents Nos. 1,690,768 and 1,690,769.

In employing the new corrosion preventive reaction products of the present invention in conjunction with such oxidized petroleum hydrocarboncorrosion preventives, the relative proportions of the two products may be varied between wide limits depending upon the degree 01' corrosion protection desired and the particular products employed. Ordinarily,.however, the new corrosion preventives are employed in amounts representing between about 25 and about 75 per cent, preferably about 50 per cent, of the combined weight of the two products.

As with the new corrosion preventive reaction products themselves, the mixtures thereof with the oxidized petroleum hydrocarbon corrosion preventives may be employed per se in applying corrosion preventive coatings to metal surfaces, but are usually more conveniently employed in the form of a solution or dispersion in a suitable liquid'vehicle, e. g., Stoddard solvent, benzene, naphtha, etc. Such liquid coating compositions usually contain between about 25 and about per cent, preferably about 50 per cent, by weight of the mixed corrosion preventives.

the new reaction products as corrosion preven- Gravity, API 48.5 Flash Point (TCC), "F' 104 Initial Boiling Point, F 312 End Boiling Point, F 394 The steel panels are removed from this solution and allowed to dry for 48 hours, during which time the solvent evaporates leaving a residual coating of the corrosion preventive material on I the panels. The panels so prepared, together with any desired "blank" panels, are then subjected to an accelerated corrosion test in a National Carbon Weathering Unit, Model X-l-A. In this apparatus, the specimens to be tested are hung on a circular rack which rotates once every 2 hours. During this period the panels are sprayed for 20 minutes with fresh water, and for the remaining hour and 40 minutes they are subjected to intense ultraviolet radiation produced by a carbon arc lamp. The panels areexamined daily for the appearance of rust, the time required for the appearance of the first rust spot being taken as a measure oi the efliciency of the corrosion preventive.

The following examples will illustrate several ways in which the principle of the invention has been applied, but are not to be construed as limiting the same.

with approximately 10 parts by weight of chromium trloxide at room temperature. The o-dimethylaminoethyl p tertiarybutyl phenol employed was a clear thin liquid product sold under the name Hyamine-B," and the chromium trioxide was employed in the form of a 20 per cent aqueous solution. The mixture was slowly heated with stirring to a temperature of about -1l5 C. and was held at this temperature until foaming subsided and practically all of the water was driven oil. The temperature was then raised to 215-230 C. over a period of about 45 minutes, and was held in this range for about 30 minutes. During the final heating period the reaction was completed and the mixture became considerably more viscous. It was then cooled and slowly poured into cold acetone. The acetone layer was decanted, and the reaction product was heated to evaporate any retained acetone. The product was then washed twice with hot water to remove any water-soluble materials, and was finally l ated to drive oil residual water. The reaction product thus obtained was a dark green liquid having the consistency of thick honey.

This reaction product was employed in preparing the following corrosion preventive liquid coating composition:

, Per cent by weight mamine-B-cros reaction product. 27.75 Alox 700 22.25

In testing and demonstrating the eiiiciency or 75 Stoddard Solvent 50.00

Alox 700 is defined by itsmanufacturer as a mixture of carboxylic bodies, alcohols, and alcoholketones obtained by the partial oxidation of petroleum fractions. It was a solid material having a melting point of 110-l20 F., a specific gravity of 09082-09176, and a saponiflcation number of 118-135. The above-described corrosion preventive composition, together with several "blank compositions, was subjected to the accelerated weathering test previously described. The results of this test are summarized as follows:

Composition ar r Per cent by ai ure 11 weight Per cent by Per cent by z gigfi Weather- Hyamine-B- weight weight M ometer :01 Reac- Hyamlne-B Alox 700 Solvent tion Product Example I! The following corrosion preventive composition was prepared employing the reaction product obtained in Example I:

Per cent by weigh t Reaction product (Example I) 4.45 Alox 700 5.55 Alox 707A 40.00 Stoddard solvent 50.00

. Example III Approximately 12 parts by weight oi the reaction product obtained in Example I and 38 parts by weight of Alox 700 which had been partially saponifled by heating with zinc oxide at 200-240 F. for 1.5 hours were dissolved in 50 parts by weight of Stoddard solvent. The resulting corrosion preventive coating composition provided protection against corrosion for 22 days when tested as hereinbefore described, whereas a composition consisting of equal parts by weight of the zinc oxide-treated Alox 700 and Stoddard solvent provided protection for only 8 days.

For purposes of providingcomparative test data, the compositions prepared in the preceding examples all comprised a reaction product otthe present class dissolved in a standard light petroleum distillate solvent. However, a variety of other solvents or liquid dispersing media may be employed to prepare a wide variety of corrosion protective compositions whose physical properties are adapted to particular application.' Thus, the reaction products herein disclosed may be dissolved or dispersed in heavier oils or the like or even in petrolatum to provide thick liquid or grease-like compositions. Similarly, the reaction products may be employed alone or in combination with other corrosion preventive materials,

particularly oxidized petroleum hydrocarbon corrosion preventives. I

Other modes of applying the principle of my invention may be employed instead of those explained, change being made as regards the ingredients or methods employed, provided the compositions set forth in any of the following claims he obtained.

I, therefore, particularly point out and distinctly claim as my invention:

1. A chromium-containing product obtained by reacting a phenolic amine compound having the general formula:

wherein R represents an alkyl group, R represents a short chain alkyl group, and n represents a whole number less than 3, with between about 5 and about 25 per cent by weight of chromium trioxide at a temperature between about 100 C. and about 250 C.

2. A chromium-containing product obtained by reacting a phenolic amine compound having the general formula:

RI CHPN/ an wherem R. represents an alkyl group and R represents a short chain alkyl group, with between about 5 and about 25 per cent by weight of chromium trioxide at a temperature between about 100 C. and about 250 C.

3. A chromium-containing product obtained by reacting a, phenolic amine compound having the general formula:

R! OH. |CH:N n

wherein R represents an alkyl group and R represents a short chain alkyl group, with between about 5 and about 25 per cent by weight oi chromium trioxide at a temperature between about 100 C. and about 250 C.

4. A chromium-containing product obtained by reacting o-dimethylaminoethyl-p-tertiarybutylphenol with between about 5 and about 25 per cent by weight of chromium trioxide at a temperature between about 100 C. and about 250 0.

PAUL R. MCCARTHY.

REFERENCES CITED The following references are of record in the file of this patent:

I UNITED STATES PATENTS Number Name Date az'zosas Sloan et al. Jan. 20, 1942 2,344,988 Kavanagh Mar. 28, 1944 2,389,090 @hields Nov. 13, 1945 EUrtaiIW PATENTS 7 Number Country Date 547,973 Great Britain Sept. 21, 1942 merm'an and Levine (1946) page 24. 

